Original name record: Melexis Technologies SA

A method is for producing a semiconductor wafer having a front side having at least one magnetic sensor element, and a back side, and an interconnection stack having at least one contact area; the method includes the steps of: m) mounting a carrier wafer to the front side; b) thinning the back side; c) providing at least one magnetic concentrator to the front side; d) providing at least one magnetic concentrator to the back side. A magnetic sensor device includes a semiconductor substrate with a magnetic sensor element, a front IMC, and a back IMC, located on opposite sides of the semiconductor substrate.